Fuel injectors, often referred to as injection valves (gasoline injectors) or injection nozzles (diesel injectors), are widely used, particularly for internal combustion engines in which they are arranged in order to dose fuel into an intake manifold of the internal combustion engine, or directly into a combustion chamber of a cylinder of the internal combustion engine. In order to enhance a combustion process in view of creation of unwanted emissions, the respective injector is suited to dose the fuel under comparatively high pressures. In case of a gasoline engine, the pressures may for example be in the range of up to over 200 bar, and in the case of diesel engines, for example in the range of up to over 2.500 bar.
Fuel injectors are manufactured in various forms in order to satisfy the needs for various combustion engines. Injection valves or injection nozzles accommodate an actuator for actuating a valve needle or nozzle needle of the fuel injector, respectively. Such an actuator is for example an electromagnetic actuator.—Fuel injectors with a ferromagnetic valve body or a ferromagnetic nozzle body undergo a magnetic flux bypass through a wall of the ferromagnetic body (cf. FIG. 2). Such a parasitic secondary magnetic flux causes a general deterioration of the dynamic responses of the respective fuel injector, i.e. the injection valve or the injection nozzle.
The secondary magnetic flux through the valve or nozzle body may be reduced by using a paramagnetic base body. However, the paramagnetic valve, nozzle or injector body reduces the overall efficiency of a magnetic circuit of an electromagnetic actuator of the respective injector, and therefore worsens the dynamic responses of the injector, in particular because it introduces a comparatively wide gap between an armature and a housing (yoke) of the actuator, as well as a pole piece and a washer (yoke) of the actuator (cf. FIG. 2).